As is known, vehicle wheels generally include a metal rim having along the perimeter ring-shaped turn-ups between which the end portions, so-called “beads” of an elastic tire, are inserted fast up and adhered.
The use is currently known of so-called “tire changing” machines for removing and fitting tires from and onto their relevant rims for carrying out, for example, inner tube maintenance, repair or replacement jobs.
Such “tire changing” machines can be, for example, of the automatic type, and are essentially composed of a supporting frame for a clamping and rotating device for clamping and rotating the rim of a wheel onto/from which the tire must be fitted/removed and of an operating unit having an operating head for fitting and removing the tire.
Such operating head is, generally, equipped with a tool for fitting the tire on the rim and with a tool for removing the tire.
The removing tool, in particular, is arranged with substantially transversal direction with respect to the longitudinal axis of the operating head and has a curved end part which is turned towards the wheel to be removed during the course of the job.
The removing tool is, generally, supported by the operating head and can be turned around a fixed axis between a configuration for pushing a side of the tire and for clamping the corresponding bead and a configuration for entraining the tire in a direction away from the relevant rim.
During use, the end part of this tool is brought up against a side of the tire and pressed against this so as to move the tire bead away from the relevant turn-up, so as to allow the tool to fasten onto the edge of the tire for subsequent moving away from the rim.
These tire changing machines have a number of drawbacks, among which the not always perfect grip of the tool for the removal on the bead, with the risk of the tool jamming between the tire and the rim. In this case, the tool must be necessarily freed manually by an operator.
To overcome this problem, the use is known of tire changing machines in which the operating head includes a pushing body with a contact surface positionable against the side of a tire and a tool for the removal of the tire which is moving between a position in which it is housed inside the pushing body and a position in which it protrudes from the body to grip the tire bead.
During use, the operating head is brought close to the tire to be removed by means of a first actuator which operates horizontally, so that the contact surface of the pushing body comes up against the side of the tire, moving it from the rim and creating a passage for the tool.
The tool is then moved outside the pushing body and fitted between the tire and the rim to grip the tire bead.
Afterwards, the operating head is moved away from the rim by the combined action of the first actuator and of a second actuator that operates vertically, so as to drag the tire outside the rim.
These known machines are however susceptible to upgrading, especially in order to ensure a correct and easy removal of the tire while providing, at the same time, more simple structure and function. The need to control and combine several actuators during the removal stage in fact calls for the presence of a computer suitable for coordinating operations, with consequent increase in the overall complexity of the machine.